The present invention relates generally to an electromechanical engine valve actuator system and more particularly to an electromechanical engine valve actuator system with a loss compensation controller for reduced armature impact.
Electromechanical engine valve actuation systems utilize electromagnetic actuators to control the movement of an armature and thereby the engine valve. Typically, the armature is moved back and forth between two electromagnets and is held against the face of these magnets depending on which one is actuated. Commonly, one electromagnet represents a closing magnet while the other one represents an opening magnet. To move the cylinder valve from an open position to a closed position, the power is shut off at the open magnet. A restoring spring begins to move the armature away from the open magnet. As the armature passed its resting position, a second restoring spring slows the armature""s movement as it approaches the closing magnet. The closing magnet is then charged with a current to capture and hold the armature into the closing position. Often, during this procedure, however, the armature may impact the face of the activated electromagnet with undesirable force. This impact can result in undesirable acoustics as well as undesirable wear on the actuator. The undesirable wear may result in low reliability and durability.
A variety of methods have been developed in an effort to reduce the impact of the actuator on the face of the actuator element. One directional approach to reducing such impact has taken the route of modifying the actuator shape in an attempt to reduce seating impact. These approaches can have negative impacts on design and production costs and leave significant room for improvement in the reduction of seating impact. Other soft seating approaches have contemplated limiting the voltage applied to the coil to a maximum valve when the armature approaches the pole face. Although this method may limit seating impact, it too leaves room for improvement. Present systems often fail to allow for adaptability once integrated into an engine system. A more adaptive system that allowed for and accommodated changes in the engine valve actuation system would be highly desirable.
In an ideal valve actuation system the valve would experience no losses during movement. In such a perfect scenario, the armature would automatically and naturally oscillate between open and closed positions and the armature velocity when it touched the opposite surface would be exactly zero. In reality, losses occur from many effects, such as friction, eddy current losses and aerodynamic forces for example. These forces prevent the armature from reaching the opposing surface without outside excitation. It is implementation that often results in negative armature impact.
It would, therefore, be highly desirable to have an electromechanical enginevalve actuation system that provided reduced actuator impact based on compensating for the armature losses such that the electromechanical engine valve actuation system has improved performance and is more adaptive and reliable than present systems.
It is therefore one object of the present invention to provide an electromechanical engine valve actuation system with a loss compensation controller for reduced armature impact. It is further an object of the present invention to provide such an electromechanical engine valve actuation system with improved flexibility and reliability in reducing actuator impact.
In accordance with the objects of the present invention, an electromechanical engine valve actuator system is provided. The electromechanical engine valve actuation system includes an armature, a first actuator, and a second actuator. A motion detector generates a signal in relation to the armature element""s position. The signal is sent to a loss compensation controller that predicts mechanical loses based on the signal. The loss compensation controller controls the first actuator and the second actuator in response to the predicted mechanical losses.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.
FIG. 1 is an illustration of an embodiment of an electromechanical engine valve actuation system in accordance with the present invention; and
FIG. 2 is a flow chart of the electromechanical engine valve actuation system in accordance with the present invention.
FIG. 3A is a cross-sectional illustration of a valve actuator in accordance with the present invention;
FIG. 3B is a top view detail of a motion detector as illustrated in FIG. 3A in accordance with the present invention;
FIG. 4A is a cross-sectional illustration of a valve actuator in accordance with the present invention;
FIG. 4B is a top view detail of a motion detector as illustrated in FIG. 4A in accordance with the present invention; and
FIG. 5 is a block diagram of loss compensation controllers of the electrical engine valve actuation system in accordance with the present invention.